Take a six-week break to give your joints time to recover, and build up some key muscles, says Bill Hartman, a strength and conditioning coach. His diagnosis: You’ve pounded the road too much, causing your fascia, tendons and ligaments to become stiff.
Do this test to see if Hartman’s right:
(1) Sit on the floor with your legs straight.
(2) Roll up a towel and place it under your heels, just high enough for the back of your knees to clear the ground.
(3) Flex your thigh muscles and press the back of your knees to the floor. They both should touch the ground equally well.
If you can’t, do this exercise:
a) Flex your thighs for 5 seconds. That’s 1 rep.
b) Do 2 sets of 15 reps, 4 times a day, until your knees match.